Effect of multiple-species starters on peptide profile and free amino acids in low-fat Kefalograviera-type cheese

Two commercially available starter culture systems, Alp DIP and a mixture of Alp DIP D and Yoghurt V1, were compared with one commercial yoghurt starter culture, CH-1, for their effect on proteolysis in low-fat (9.5%) high-moisture (49.6%) Kefalograviera-type cheese. A full-fat control cheese (30.8% fat, 37.7% moisture) was also made with the CH-1 culture using a modified scalding procedure. The effect of the multiple-species cultures on primary casein breakdown in low-fat cheeses, as assessed by polyacrylamide gel electrophoresis, was small but secondary proteolysis, as assessed by reversed-phase HPLC determination of the total free amino acid content of the cheeses, was significantly (p < 0.05) enhanced. Experimental cheeses had a richer peptide profile and a generally higher free amino acid content than the controls. Cheeses were clearly separated according to the starter culture and to the scalding temperature using principal component analysis of the results from reverse-phase HPLC chromatograms of the water extracts and from individual free amino acid content.